用C语言编写一个功能丰富的定时器，可以设定起止时间及设置了暂停键和继续键，另外还增设了加计数定时和减计数定时-C language prepared by a feature-rich timer, you can set the start and end time and set the pause button and continue key, in addition to the creation of the timing of counting up and down counti